Increased density and proximity of both active and passive electronic device structures in an integrated circuit have been recognized to provide benefits in both performance and functionality of integrated circuits. For example, reduced lengths of signal propagation paths allow operation at higher clock rates while reducing susceptibility to noise. Increased numbers of devices on a single chip also generally support such improved performance while allowing a greater number and variety of circuit functions to be provided such as local voltage regulation and conversion, local memory and additional logic circuitry or coprocessors for microprocessors, non-volatile storage, redundant circuitry, self-test arrangements and many other types and combinations of circuits.
However, such increases in integration density and performance require improved control of various device parameters. One such parameter is the step height, which is the difference in height between the tops of two layers within a semiconductor structure. A consistent step height is important for repeatability and consistency amongst various manufactured samples of a particular type of semiconductor device.